KUNMING - Four badly injured people have been rushed to Kunming, capital of Southwest China's Yunnan province, for treatment after an explosion in the area killed three and injured 14 others on Thursday morning, local authorities have said.

The 10 less injured people have been sent to a local hospital in Qiaojia county, according to the county committee of the Communist Party of China.

The incident occurred at around 9 am in Qiaojia county, Zhaotong city, the committee said.

While the cause of the explosion is under investigation, it has been reported that it was a bombing.

According to the Weibo account of a Kunming metropolis newspaper, a witness said a female went to the demolition bureau with explosives after she was asked to sign an agreement on house relocation, setting them off at the site.

The bomber and two demolition bureau staff members died at the scene, the newspaper wrote on Sina Weibo, a popular Twitter-like microblogging site.